Structures and Other Properties of Polyynes and their Isomers: Theoretical and Experimental Results - Polyynes: Synthesis, Properties, and Applications - page 404

FIGURE 17.2 Intensities of the strongest IR lines which in all HC m H molecules are
due to the asymmetric C-H stretch.
FIGURE 17.3 Drift of the wavelengths of the strongest IR line of the HC m H
molecules.